After all the ways the government rules have made my purchases worse, I'm inclined trust these companies more, not less.
Watch some documentary footage on children with lead poisoning from leaded gas.
Report back your findings.
I was highlighting ways in which these regulations have made our lives better.
Answering your question, I agree. If we were to defeat those things that make modern diesels better as the parent commenter is suggesting, it would make the air worse.
The vast majority of owners fucking with the emissions equipment on their modern diesels are not doing so to conspicuously assault other motorists/cyclists/pedestrians with soot; they are doing it because in pursuit of that last 10% of emissions cleanup, regulators have burdened the operators of diesel trucks with hundreds of pounds of multi-thousand-dollar components that are delicate, MUST be maintained, reduce engine power by 25% and fuel efficiency by 50%.
If you just tow a boat, or a camper, that's annoying. If you use the truck for an actual business...that's HUGE expense.
Bear in mind, the typical diesel delete isn't something you notice if the person is driving normally in a modern truck. Electronic engine management and electronic common-rail injection are in new trucks, and they're night and day vs. mechanical injection on old diesels.
I have seen this with the current 6.7 Ford Scorpion-series Powerstroke V8 in an F-350.
With the emissions-controls reduced to what was legally required in 2003, a new-ish Mercedes E-class diesel is efficient enough to drive from Framingham MA to Beloit WI on a single tank of fuel, at highway speeds.
But we don’t have terrible air quality (except for when fires burn forests that greenies said we needed to protect, and made worse in the end). So I’m not sure what I’m supposed to be researching.